1. Field of the Invention
The present invention relates generally to speed change gear systems, and more particularly to a speed change gear system adapted for a power shift transmission mechanism of an industrial vehicle.
2. Description of the Prior Art
It is desirable that the gear type speed change mechanism utilized upon industrial vehicles, such as for example, fork lifts and shovel cars, should have speed ratios of 1:2:4 in a three-stage speed change gear train so that a shockless shifting and compact assembly may be available, and alternatively a speed ratio of 1:2 in a two-stage system.
In addition, the number of forward and rearward speeds as well as the gear ratios thereof should preferably be the same, since the frequency of use of such forward and rearward movements are approximately the same within such industrial vehicles.